The position and placement of a fastener, such as a bolt, screw, or nut, does not always permit the use of conventional tools to facilitate the installation and removal of the fastener. This is particularly true when there is only minimal clearance in the area surrounding the fastener such that it is impossible to engage the fastener with a conventional tool (e.g., as in the attachment of vehicle doors to the vehicle body during assembly). Particularly, the relative position and proximity of a vehicle body to a vehicle door (e.g., the hinge portion of the door) does not permit the use of a conventional impact gun where the drive mechanism is located directly behind the socket that engages the fastener.
To overcome this problem, tool attachments have been produced that facilitate the use of conventional power tools to engage a fastener located in an otherwise inaccessible position. These attachments, also known as crow's foot attachments, can be affixed to the power tool and engaged with the drive mechanism of the power tool. FIG. 1 shows an example of a prior art crow's foot tool attachment. The attachment 2 comprises a shaft 4 having a socket 6 fixed thereon. The socket 6 is connected to the shaft 4 with a swivel joint (not shown), such as a ball and socket joint, that permits the socket 6 to be adjustably positioned on the end of the shaft 4. The opposite end 10 of the shaft is configured to attach to the drive mechanism 12 of a power tool 14 having an axis of rotation 18 and a plane of rotation 20. When engaged with a fastener 16, the socket rotates about a second, different axis of rotation 38 and in a second, different rotation plane 30.
While generally suitable for the purpose of engaging otherwise inaccessible fasteners, the existing tool attachments have several drawbacks including tool slippage and stripping of the fastener 16. This is because the force F applied to the power tool 14 to keep the socket 6 engaged with the fastener 16 has both a perpendicular component 44 and a parallel component 45 relative to the socket 6. The perpendicular component 44 of the force F causes the operator to have poor control over both the fastener 16 and the power tool 14 at the interface of the fastener 16 with the socket 6 resulting in slippage of the socket 6 on the fastener 16. Slippage of the socket 6 on the fastener 16 may cause the fastener 16 to become stripped necessitating removal and replacement of the fastener 16. If the socket 6 becomes fully disengaged from the head of the fastener 16 during installation or removal of the fastener 16, damage may occur to the workpiece 50 as the rotating attachment 2 comes in contact with portions of the workpiece 50.
Other embodiments of prior tool attachments include those that are configured to be affixed to specialized power tools and engaged with the drive mechanism of the power tool such that the rotational motion of the drive mechanism is translated to a different rotational axis and plane. Such attachments use gears, shafts, and spline gears to translate the rotational motion of the power tool. However, these tools suffer from the same slippage problems as the apparatus shown in FIG. 1. Further, such attachments are expensive (as are the specialized power tools required for operation), the translation mechanism is often intricate, heavy, and susceptible to breakage, and repair of the mechanism can be difficult and time consuming.
Accordingly, a need exists for an inexpensive, ergonomically correct, versatile, and easily operated tool attachment for facilitating the insertion and removal of fasteners in otherwise inaccessible locations.